1. Field of the Invention
This invention relates generally to solid state accelerometers and gyroscopes for guidance and control systems, and more particularly to solid state accelerometers and gyroscopes that utilize fiber optical transducers and modulators.
2. Description of the Prior Art
Cost, performance limitations, and reliability problems of mechanical gyros and accelerometers have stimulated the development of solid state fiber optic gyros. Presently, ring laser gyros have demonstrated reliable performance and have been widely accepted as the state of the art in gyroscope technology for high performance applications. However, ring laser gyros are not completely solid state and require large and costly high quality optical components. Although investigators have been increasing the effectiveness and reliability of ring laser gyros, no genuine breakthrough in a low cost solid state gyro with wide dynamic range capability has occurred using the ring laser gyro concept.
A completely solid state fiber optical gyro having a wide dynamic range was disclosed in U.S. Pat. No. 4,299,490, issued to Richard F. Cahill, et al on Nov. 10, 1981 entitled "Phase Nulling Optical Gyro" and assigned to the assignee of the instant application. This patent advanced the fiber optic gyro technology by allowing the fiber optical gyro to have performance characteristics similar to those of the ring laser gyro while maintaining the advantages of a solid state embodiment.
It is an object of this invention to add accelerometer capabilities to guidance and control systems having a frequency output scheme that is compatible with demodulation methods used in fiber optical gyros such as the one described in the reference patent. Another object of this invention is to allow accelerometers to be multiplexed with the fiber optical gyros to form a multi-sensor capable of measuring both acceleration and rotation.